In the process of converting two-dimensional (2D) motion picture images into three-dimensional (3D) motion picture images, each frame of the motion picture has another perspective of the image created that perhaps was not originally recorded. This is referred to as a complementary image. Reconstructing the complementary image is done by applying algorithms that cause pixels to be shifted along the horizontal axis of the image.
In the process of creating a 3D perspective image out of a 2D image, various objects or portions of objects within the image are repositioned. If an image object requires repositioning along the horizontal, or X axis, to effectively position the object toward or away from the viewer, the repositioned object covers up existing pixels on one side of the object and creates a gap of missing pixels on the other side of the object. This gap of missing pixels may also be referred to as the pixel fill area. For example, if an object is placed in the foreground, that object in a newly-created right view will be positioned to the left, covering over pixels on its left edge. As objects shift their position, they cover up existing pixels in the direction that the object moves, and leave a gap of missing pixel information on the other side of the object.
In U.S. patent application Ser. No. 09/819,420, it was disclosed (“Repeat Pixel” feature) that the missing gap of pixels can be filled by repeating pixels from the edge of the background object that the object is moving away from. In many cases, this approach is sufficient even though the pixel repeat information is not an exact replica of the pixel information that should actually be present in the gap of missing information. As long as the pixel repeat gap is not extensively large (which would occur if the object happens to move a great distance toward or away from the viewer) and as long as the repeat pixel information does not exhibit any type of motion artifacts relative to its adjacent surrounding backgrounds, simply “pixel repeating” background pixels across the gap often goes unnoticeable.
One of the reasons that pixel repeating can go unnoticed is that the pixel repeating occurs in only one image and is therefore seen by only one eye. In effect, it is part of a three-dimensional disparity. The brain interprets depth by differences of what we perceive with our left and right eye of an image. The fact that the image seen by one eye contains pixel repeat information can, in many cases, go quite undetectable. Even in a real photographed 3D image, the edges of foreground against background result in edges differences between the left and right eye views.
It is the consistency and uniformity of the content along the edges of objects that the brain evaluates to determine whether an image should be accepted as a legitimate coherent 3D image, rather than an image with distracting artifacts. If the edges start to become out of context with the surrounding background, either by size or shape for example, the brain will tend to interpret and sense these areas of the image as artifacts. It is when the differences become too great and inconsistent with the flow of the image content that the brain stimulates human senses to consciously perceive such image artifacts as distracting and/or unreal.
There are some cases in the process of converting two-dimensional images into three-dimensional images where the background information around a surrounding object does not lend itself to pixel repeating. This may either be because the gap is too wide or because there may be too much activity of motion near the edge of the object by other objects. In this case, the area of pixel fill is simply not a good fit and results in a visual distraction.
In view of the foregoing, it would be desirable to be able reduce or eliminate image artifacts that occur in the process of applying depth to objects during the conversion of 2D images into 3D images.